Industry
Waste Water Treatment
Open impellers, polymer wetted parts and vertical sump pumps for screened sewage, return sludge, effluent and pit drainage.
Read more
CN Series
ANSI CN Series Water Centrifugal Pump
End-suction water pump built to ANSI/ASME B73.1 with a full open impeller and ANSI B16.5 flanges
Overview
An ANSI B73.1 footprint means the pump you buy today can be replaced by any B73.1 pump tomorrow. That is the whole point of the standard and the reason the CN series exists.
The CN series is an end-suction, single-stage water pump designed and manufactured to ANSI/ASME B73.1, the American dimensional standard for horizontal end-suction centrifugal pumps. Sizes run from 1 inch to 10 inch with capacity to 400 m³/h.
Because the casing, baseplate and shaft extension follow B73.1, a CN pump drops into a foundation that was laid for another B73.1 pump without new grouting, new pipe spools or a new motor stool. Plants standardised on ANSI hydraulics use that interchangeability to cut the spare parts they hold.
The CN uses a full open impeller and a single mechanical seal. Open impellers tolerate the suspended solids typical of raw water and treated effluent better than closed impellers, and they let the running clearance be reset from the outside as the pump wears.
ANSI B73.1 CN series end-suction centrifugal pump with open impeller and cast iron casing
Key Benefits
What This Pump Does Better
- Dimensionally interchangeableCasing, baseplate and shaft follow ANSI/ASME B73.1, so the pump matches the footprint of any other B73.1 unit of the same size.
- Flange options for existing pipeworkANSI B16.5 150LB and 300LB flanges in flat face or raised face, so the pump lands on the pipe class already in the plant.
- Open impeller for dirty waterThe full open impeller passes the stringy and granular solids found in waste and water treatment duties without the vane blockage a closed impeller suffers.
- Four frame sizesS, M, L and XL power frames let the bearing and shaft be sized for the duty rather than forcing one frame across the whole range.
- Materials matched to the waterCast iron, ductile cast iron, carbon steel and SS304 wetted parts cover raw water through to mildly corrosive treated effluent.
In the Works
The Pump and How It Is Built
Application Scenarios
Where This Pump Is Put to Work
- Waste water treatmentLifting screened raw sewage, return activated sludge and final effluent between process stages.
- Potable water treatmentTransfer duties around clarifiers, filters and clear wells where an ANSI footprint is the plant standard.
- Industrial water serviceGeneral plant water, cooling tower make-up and wash-down supply on sites that specify B73.1 pumps.
- Pump replacement projectsDirect swaps into existing ANSI baseplates where the original pump is no longer supported.
Who It Is For
- EPC contractors and consulting engineers writing ANSI/ASME B73.1 into a water or waste water specification.
- Municipal and industrial water plants that already hold ANSI spares and do not want a second dimensional standard on site.
- Distributors supplying markets where ANSI flanges and inch sizing are the norm rather than DIN.
Problems It Solves
What It Is Chosen to Fix
- A discontinued pump on an existing baseplateA B73.1 replacement bolts to the same holes and the same pipe centreline, so the civil work and the pipe spools stay as they are.
- Impellers blocking on solids-bearing waterThe full open impeller has no shroud for rags and fibre to wrap behind.
- Clearances opening up as the pump wearsOpen impeller running clearance is reset externally, which restores head without stripping the wet end.
- Two dimensional standards in one plantStandardising on B73.1 lets one set of casings, seals and bearings cover more of the pump population.
Technical
Features and Specifications
Every value below is taken from the Flowsteer product catalogue. Values the catalogue does not publish are marked TBC rather than estimated.
Technical Features
- End-suction, single-stage, back-pull-out construction
- Designed and manufactured to ANSI/ASME B73.1
- Full open impeller
- Single mechanical seal
- S, M, L and XL power frames
- ANSI B16.5 150LB and 300LB flanges, flat face or raised face
Specifications
| Pump type | End-suction, single-stage, horizontal |
|---|---|
| Design standard | ANSI/ASME B73.1 |
| Size range | 1 in to 10 in |
| Capacity (Q) | Up to 400 m³/h |
| Impeller type | Full open |
| Shaft seal | Single mechanical seal |
| Power frames | S, M, L, XL |
| Flange standard | ANSI B16.5 150LB FF/RF and 300LB FF/RF |
| Casing materials | Cast iron, ductile cast iron, carbon steel, SS304 |
| Head (H) | TBCnot published on the source catalogue |
| Speed | TBCnot published on the source catalogue |
Materials
Wetted Materials and What They Are For
- Cast ironThe default casing material for clean and screened water at ambient temperature.
- Ductile cast ironChosen where the casing has to carry higher pressure or heavier pipe loads than grey iron allows.
- Carbon steelUsed where a steel casing is specified for mechanical strength or for welding repairs in the field.
- SS304For treated effluent and process water that would rust a ferrous casing.
Customisation
What You Can Specify on This Pump
- Flange rating: 150LB or 300LB, flat face or raised face
- Casing material: cast iron, ductile cast iron, carbon steel or SS304
- Power frame: S, M, L or XL to suit the duty and the driver
- Bare shaft pump, or complete set with motor, coupling, guard and baseplate
Certifications, production capacity and export markets are not published in the Flowsteer catalogue, so this site does not state them. Tell us what your project needs evidenced and we will confirm in writing.
How It Compares Within the Range
| Series | Published Envelope | Best Suited To |
|---|---|---|
| ANSI CN Series | ANSI/ASME B73.1, inch sizing, full open impeller | Plants and specifications built around the American standard |
| ISO CI Series | ISO 2858 / ISO 5199, metric sizing, closed impeller | European and ISO-specified projects needing interchangeable metric hydraulics |
| FA Series | BS EN733 / DIN24255, DN32 to DN250 | Building services, fire and irrigation duties on DIN pipework |
Use Guide
Getting This Pump Right on Site
- Confirm the duty point in m³/h and metres of head before selecting a frame size; the four frames are not interchangeable once the shaft is sized.
- Check the pipe flange rating on site. A 300LB pump will bolt to a 150LB flange pattern in some sizes but the gasket face and bolt loads differ, so match the rating.
- Set the open impeller clearance during commissioning and record it. Re-setting the clearance later is the cheapest way to recover lost head.
- Keep the suction line short and straight. An open impeller is tolerant of solids but not of a starved suction.
Related
Industries Solutions and Guides
Industry
Municipal Water Supply
Transfer, distribution and booster duties on city water networks, with EN733 and ANSI footprints and a bronze impeller as standard.
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Solution
Back Pull-Out Maintenance
Four of the five Flowsteer series use back pull-out construction. Here is what that changes about a maintenance window.
Read moreSolution
Pump Material Selection
Cast iron through to UHMW-PE. How the Flowsteer range maps onto water that ranges from clean to chemically hostile.
Read moreStandards Guide
ANSI/ASME B73.1 Explained
B73.1 is a dimensional standard, not a performance standard. Knowing the difference is what makes a replacement pump drop straight onto an existing baseplate.
Read moreDesign Guide
Open vs Closed Impellers
Efficiency on one side, solids passage and adjustability on the other. The choice is decided by the water, not the pump.
Read moreMaterial Guide
Pump Materials Guide
Grey iron through to UHMW-PE. What each wetted material is for, and the failure it is chosen to prevent.
Read moreAlso in the range
Related Products
CI Series
ISO CI Series Water Centrifugal Pump
ISO 2858 and ISO 5199 back-pull-out end-suction pump, fully interchangeable with other ISO brands
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FA Series
FA Series EN733 Horizontal Centrifugal Pump
BS EN733 / DIN24255 end-suction pump, 2 to 1100 m³/h and head to 152 m, for building services fire and irrigation
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DE Series
DE Series Water Centrifugal Pump
Process-duty water pump from DN 25 to DN 400 with flow to 600 m³/h for water and waste water
View specificationsQuestions
ANSI CN Series Water Centrifugal Pump FAQ
What does ANSI/ASME B73.1 actually fix on the pump?
It fixes the external dimensions: the foot and baseplate bolt pattern, the centreline height, the suction and discharge flange positions and the shaft extension. Two B73.1 pumps of the same size interchange mechanically even if the hydraulics inside differ.
Can the CN series handle water with suspended solids?
Yes. The full open impeller is chosen for waste and water treatment duties because there is no shroud behind the vanes for fibre to collect on. The source catalogue does not publish a maximum solids percentage for this series, so confirm the solids loading with us before ordering.
Which flange rating should I order?
Match the pipe class already installed. We supply ANSI B16.5 150LB and 300LB, both in flat face and raised face. Tell us the line rating and gasket type and we will quote the matching pump.
What is the maximum capacity?
400 m³/h across the 1 inch to 10 inch range. Head and speed are not published in the source catalogue for this series — send us the duty point and we will confirm what the selected size will do.
Do you supply the pump bare shaft or as a complete set?
Both. A bare shaft pump suits a rebuild where the motor and baseplate stay; a complete set arrives with motor, coupling, coupling guard and baseplate aligned.
Request a Quotation for the CN Series
Send the duty point and the liquid description and we will confirm the size, the materials and any specification this page marks TBC.